The overall goal of the Transgenic/Knockout Rodent Core offers state-of-the-art services for the manipulation of mouse and rat genomes, ensuring that the primary beneficiaries of CCSG-supported Shared Resources have the best information and technical resources available to support cancer research. The Core, which is Cancer Center managed, was established in 1993 to produce transgenic and knockout mice for USC Norris members and to increase the use of mouse technology through education and consultation to the cancer research community. Since its inception, the Core has operated under the same faculty leader, Dr. Robert Maxson, and manager, Dr. Nancy Wu; it has also been continuously funded by the CCSG. The Core is widely recognized within the USC community and beyond for the high quality of its services. The Core produces transgenic and knockout mice and offers two important new services, knockout rats and CRISPR/Cas9- mediated gene editing in mice. Using ES cell technology pioneered by Dr. Qi-Long Ying at USC, the Core generated the first knockout rats. The new CRISPR/Cas9 technology will make it possible to produce gene knockouts much faster and at lower cost than current ES cell-based technology. The Core continues to be active in education and consulting services, and provides a number of important ancillary services, including in vitro fertilization, and re-derivation of mouse strains, as well as cryopreservation of embryos. At the last CCSG renewal, the Core received a merit rating of ?excellent? with reviewers noting the competence of the Core leadership and the high quality of the work. The only criticism was low usage by Cancer Center members, although it was recognized that the Core serves the entire USC community. We have stepped up efforts to promote the availability of the Core and encourage cancer investigators to use Core services in their research. In the most recent year, 12 peer-review funded members, or 71% of total users, from four Research Programs (Epigenetics and Regulation, Gastrointestinal Cancers, Molecular Genetics, and Tumor Microenvironment) used the Core to accomplish their research objectives.